That road salt you see sprinkled on sidewalks and roads to melt snow and ice can persist in the environment for years or even decades after the season ends. New research from the College of Engineering tracks how those deicing agents — soluble, corrosive and difficult to remove — later end up polluting aquatic ecosystems and interfering in the water treatment.
“A deicing agent works by lowering the freezing point of water, preventing ice from forming at its normal freezing point,” explains Assistant Professor Amanda Carneiro Marques, whose research focuses on methods of protecting water quality. “The decision about the most adequate deicing agent to apply depends on the characteristics of the area, logistical planning — which can be related to cost — and effectiveness at different temperatures. For example, some chloride-based salts have the potential to produce less environmental impact than others, but they can be more expensive or not as effective for specific weather and road conditions.”
Marques has identified chemical markers for pollutants that can be tracked to see how and when they might end up in, say, a nearby river. She uses chemical analysis and environmental tracers to map its movements and models the effectiveness of mitigation strategies. The results have supported local government agencies and conservation departments to develop ways to avoid over-salting and to educate the public about the environmental impact of deicers.
“Because salt is persistent in the environment, real-time technology, environmental education and research are necessary to understand factors that can contribute to increasing salt trends in the environment and support an effective implementation of mitigation strategies to guarantee the quality of our freshwater resources,” she says.
Understanding the human health and environmental impact from deicing agents can only be done when considering factors like location, length of application time, environmental conditions and transportation use, she says. Every winter, and season, can be used to identify repeating patterns and vulnerable hotspots, and also develop effective alternatives to treat the area and minimize further water degradation. DM
